Peptide quantification by liquid chromatography-mass spectrometry (LC-MS) combines the high resolving power of reversed-phase (RP) chromatography with the excellent selectivity and sensitivity of mass spectrometric detection. On the basis of comprehensive practical experience in the analysis of small molecules, pharmaceutical research is developing technologies for analysis of a growing number of peptidic drug candidates. This article is a detailed review of procedures based on LC-MS techniques for quantitative determination of peptides. With the focus on pharmaceutical applications several technologies for sample preparation, various aspects of peptide chromatography, important characteristics of ESI-MS, selectivity of MS-detection modes, the large variability of internal standards, and modern instrumentation are discussed. The demand for reliable, robust, sensitive, and accurate methods is discussed using numerous examples from the literature, complemented by experiments and results from our laboratory.

Standard reference materials (SRMs) are homogeneous, well-characterized materials used to validate measurements and improve the quality of analytical data. The National Institute of Standards and Technology (NIST) has a wide range of SRMs that have mass fraction values assigned for legacy pollutants. These SRMs can also serve as test materials for method development, method validation, and measurement for contaminants of emerging concern. Because inter-laboratory comparison studies have revealed substantial variability of measurements of perfluoroalkyl acids (PFAAs), future analytical measurements will benefit from determination of consensus values for PFAAs in SRMs to provide a means to demonstrate method-specific performance. To that end, NIST, in collaboration with other groups, has been measuring concentrations of PFAAs in a variety of SRMs. Here we report levels of PFAAs and perfluorooctane sulfonamide (PFOSA) determined in four biological SRMs: fish tissue (SRM 1946 Lake Superior Fish Tissue, SRM 1947 Lake Michigan Fish Tissue), bovine liver (SRM 1577c), and mussel tissue (SRM 2974a). We also report concentrations for three in-house quality-control materials: beluga whale liver, pygmy sperm whale liver, and white-sided dolphin liver. Measurements in SRMs show an array of PFAAs, with perfluorooctane sulfonate (PFOS) being the most frequently detected. Reference and information values are reported for PFAAs measured in these biological SRMs.

In 1993, the Health Services Research Committee of the American Society of Clinical Oncology (ASCO) charged an Outcomes Working Group with defining the outcomes of adult and pediatric cancer treatment to be used for technology assessment and development of cancer treatment guidelines. The Working Group defined by consensus outcomes for technology assessment and guideline development, focusing on cancer treatments. The Working Group considered a variety of perspectives on outcomes, including those of patients, physicians, clinical investigators, ASCO, and policy makers. Because ASCO's guidelines will define what constitutes the best treatment and not whether that treatment should be paid for, the Working Group gave higher priority to the clinical and clinical research perspectives than to the health policy perspective. Survival is the most important outcome of cancer treatment. An improvement in at least disease-free survival is a prerequisite for recommending adjuvant therapy. In the case of metastatic cancer, treatment can be recommended even without an improvement in survival, if it improves quality of life. Quality of life includes global quality of life, as well as its physical, psychologic, and social dimensions. To be an outcome of cancer treatment, quality-of-life measures must be sensitive to clinically meaningful changes produced by treatment; evaluations must control for placebo effects and determinants of quality of life not related to cancer or its treatment. Toxicity, both short and long term, is vitally important, with the latter being particularly critical in children. The value of cancer outcomes like tumor response (eg, complete or partial response) and biomarkers (eg, CA-125) for technology assessment and guideline development depends on their ability to predict patient outcomes (survival and quality of life) or to influence decisions about treatment. Complete response is an important outcome when it predicts survival. Progression is important because it signals the need to change or stop treatment. Cost-effectiveness is an especially important outcome to consider when the benefits of treatment are modest or the costs are high. Patient outcomes (eg, survival and quality of life) should receive higher priority than cancer outcomes (eg, response rate), but both types of outcomes are important in technology assessment and guideline development. Multiple outcomes should be considered because no single outcome adequately describes the results of cancer treatment. In general, there is no minimum benefit above which treatments are justified; rather, benefits should be balanced against toxicity and cost.

Neurological examination of parkinsonian symptomatology encompasses a range of procedures that gauge the status of the extrapyramidal motor system. 1 These procedures typically consist of clinical rating scales, that estimate motor function but are variable from one examiner to the other and are relatively insensitive to subtle disease. [1][2][3][4] The subjective impression of the parkinsonian patient by the examiner may also influence the scores. 1 As a result, investigators have developed complex quantitative instruments for objective assessment of parkinsonian motor impairment. 4,5 These instruments objectively assess tremor and motor slowness, characterized by two components: failure to initiate a willed movement (akinesia) and A B S T R A C T: Background: Various investigators have developed complex quantitative instrumental procedures for objective assessment of parkinsonian motor impairment, since drawbacks of rating scales are interrater variability, subjective impression, and insensitivity to subtle modifications. O b j e c t i v e s : To determine whether performance of inserting of pegs and tapping (i) correlates with each other (ii) d i ff e r e n t i a t e s between parkinsonian subjects and healthy controls and (iii) reflects severity of Parkinson's disease (PD). Subjects and methods: In 157 previously untreated idiopathic parkinsonian patients and healthy controls, we measured (i) the total time taken to insert 25 pegs from a rack into a series of appropriate holes in a Purdue pegboard-like apparatus and (ii) the number of taps on a contact board with a contact pencil for a period of 32 seconds for assessment of fine motor skills. Results: Results of both tests correlated with each other, differed between parkinsonian subjects and controls and reflected scored severity of PD. Better correlation with intensity of PD was noted with the Purdue pegboard-like task. Conclusion: Both tapping and inserting of pegs represent useful tools for objective evaluation of severity of PD. Peg insertion correlated better with disease severity. Both approaches may be useful in future clinical studies. RÉSUMÉ: Corrélation entre le tapping et la planche à chevilles dans la maladie de Parkinson. Introduction:Différents investigateurs ont développé des méthodes instrumentales quantitatives complexes pour l'évaluation objective du déficit moteur parkinsonien à cause des inconvénients inhérents aux échelles d'évaluation, soit la variabilité entre les observateurs, la subjectivité et le peu de sensibilité à des modifications subtiles. Objectifs: Déterminer si la performance au tapping et à la planche à chevilles (i) sont en corrélées (ii) identifie les parkinsoniens et les contrôles et (iii) reflète la sévérité de la maladie de Parkinson (MP). Sujets et Méthodes: Nous avons mesuré (i) le temps total pour transférer 25 chevilles d'un support à une série de trous appropriés dans une planche à chevilles de type Purdue et (ii) le nombre de percussions avec un stylet sur une surface de contact pendant une période de 32 seconde...

The tetraspanin CD63 is implicated in pro-metastatic signaling pathways but, so far, it is unclear, how CD63 levels affect the tumor cell phenotype. Here, we investigated the effect of CD63 modulation in different metastatic tumor cell lines. In vitro, knock down of CD63 induced a more epithelial-like phenotype concomitant with increased E-cadherin expression, downregulation of its repressors Slug and Zeb1, and decreased N-cadherin. In addition, b-catenin protein was markedly reduced, negatively affecting expression of the target genes MMP-2 and PAI-1. b-catenin inhibitors mimicked the epithelial phenotype induced by CD63 knock down. Inhibition of b-catenin upstream regulators PI3K/AKT or GSK3b could rescue the mesenchymal phenotype underlining the importance of the b-catenin pathway in CD63-regulated cell plasticity. CD63 knock down-induced phenotypical changes correlated with a decrease of experimental metastasis whereas CD63 overexpression enhanced the tumor cell-intrinsic metastatic potential. Taken together, our data show that CD63 is a crucial player in the regulation of the tumor cell-intrinsic metastatic potential by affecting cell plasticity.Metastasis is the major cause of death in cancer patients suffering from solid tumors. 1 Epithelial-mesenchymal transition (EMT) is a prerequisite for successful dissemination and colonization of secondary organs by tumor cells. 2 EMT has been shown to result in increased cancer cell motility by reorganization of actin filaments, downregulation of E-Cadherin and increased expression of N-Cadherin. 2-4 Molecular regulators of EMT are the transcription factors Snail, the bHLH and ZFH protein families (Zeb1 and Zeb2), which suppress the gene expression signature assigned to the epithelial phenotype. 3,5 MicroRNAs (miRNAs), including members of the miR-200 family, for example miR-141, have been shown in turn to suppress Zeb proteins, adding an additional level of regulation. 6 In addition, b-Catenin, which is regulated by Glycogen synthase kinase 3 beta (GSK3b) phosphorylation, 7 is shown to play a decisive role in EMT-induction by its ability to both, sense E-Cadherin status and control gene expression of target genes like MMP-2 and PAI-1. 4 EMT is regulated by different cytokines and growth factors, including TGF-b1. 3 Mesenchymal-to-epithelial transition (MET) gained recognition as a crucial process for successful metastasis formation, as tumor cells switch back to a more epithelial phenotype at the site of metastatic outgrowth. 5 Therefore, cellular plasticity and regulation of these alternating phenotypes are of importance during metastatic cancer progression. 5 Tetraspanins seem to play a role in cancer progression. Some family members are described to exert pro-metastatic properties, whereas others are reported to inhibit metastasis. 8 This protein family displays four membrane-spanning domains and their ability to form multiprotein complexes by interacting with other tetraspanins and also with a variety of other transmembrane and cytosolic proteins. [9][10][11] ...